Lighting devices having switchable lighting properties are known in the art. US2015/0055335, for instance, describes a day/night switchable light adjusting device and a light adjusting method. The day/night switchable light adjusting device is composed of a plurality of panels; each panel includes a reflecting surface and at least one lighting unit. Each lighting unit can emit various wavelength region lights, and the various wavelength lights are mixed on a light collecting component. A control unit is provided for adjusting the various wavelength region lights corresponding to day/night variation. A light intensity of a cyan region light or a blue region light is reduced for preventing an over-inhibition on a quantity of Melatonin.